SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc1881f86b58fd0341ebae7c66533b957872cddf2a1d08e4a644ffa2944afec5' 
  AND token = 'gzwc6svUOxgjNpD1hE2jQdCJhUSAVWQSZzUf/TzXc5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}